hy did big-brained Homo sapiens suddenly emerge some 150,000 years ago? In this provocative new book, Leonard Shlain, author the bestselling Art & Physics and The Alphabet Versus the Goddess argues that profound alterations in female sexuality hold the key to this mystery.

Long ago, due to the narrowness of her bipedal pelvis and the increasing size of her infants’ heads, the human female began to experience high childbirth death rates, precipitating a crisis for the species. Natural selection adapted her to this unique environmental stress by drastically reconfiguring her hormonal reproductive cycle. Her estrus disappeared and menses mysteriously entrained with the periodicity of the moon. Women formulated the concept of a month, which in turn allowed them to make the connection between sex and pregnancy. Upon learning the majestic secret of time these ancestral females then gained the power to refuse sex when they were ovulating. Men were forced to confront women who possessed a mind of their own.

Women taught men about time and the men used this knowledge to become the planet’s most fearsome predator. Unfortunately, they also discovered that they were mortal. Men, then invented religions to soften the certainty of death. Subsequently, they belatedly grasped the function of sex. The possibility of achieving a kind of immortality through heirs drove men to construct patriarchal cultures whose purpose was to control women’s reproductive choices.

Leonard Shlain explores how these archaic insights about sex, time and power dramatically altered all subsequent human cultures, from the nature of courtship to the institution of marriage to the evolution of language. Along the way, the author also offers innovative and provocative theories concerning the human origins of menstrual harmony among closeknit women, homosexuality, superstition, masturbation, early menopause, circumcision, left-handedness, baldness, color blindness, sadism, and orgasms. His book also addresses the reasons why humans have the deepest capacity to love each other over the longest periods of time compared to any other animal. Sex, Time & Power is a compelling book that challenges accepted views of human sexuality and is sure to stimulate new thinking about old matters.